When you're packing the sunscreen, make sure to bring some bottles of water too. Here are five reasons why.

Reasons to Stay Hydrated

It Boosts Brainpower

Next time you feel like you are reacting a bit slow to your friends' jokes, consider drinking some water.

According to a new study published in the journal Frontiers in Human Neuroscience, drinking water when you feel thirsty can help you think and act. The participants who drank water before performing a series of cognitive tasks reacted faster than those who did not.

"If the slower reaction times translated into real world performance, it could mean that people are generally a little slower at performing tasks," says Dr. Caroline Edmonds, senior lecturer in psychology at the University of East London, who was involved in the study.

Reasons to Stay Hydrated

It Helps Maintain the Balance of Body Fluids

Did you know more than half of your body is composed of water? All this water helps with critical functions like maintaining body temperature, cushioning and protecting vital organs and aiding in digestion.

On hot days, your body loses water through increased sweating. And not drinking about water can interfere with your body's necessary functions. This can lead to dehydration and if untreated, can develop into heatstroke or heat exhaustion.

So if you feel like you need to eat something, try drinking a glass of water first. A lot of times it will help.

Water may not magically help you lose weight overnight, but substituting higher calorie drinks for water will reduce a large amount of calorie intake. Also, in order to burn calories, an adequate amount of water is needed. Staying hydrated will also keep things in your intestinal tracts flowing.

"You need to have adequate water to have regular bowel movements," says Cimperman. The consequence of not drinking enough water? Constipation.

Reasons to Stay Hydrated

It Will Improve Your Mood

Lack of sleep isn't the only cause of headaches, irritability and fatigue. Studies suggest that increasing your daily amount of water intake can reduce the duration and intensity of headaches.

When your body is low on water, blood vessels will dilate, causing swelling and worsening the feeling of a headache. According to the NIH, if you're experiencing dizziness, this is a sign of dehydration. You should drink small amounts of water slowly over time.

Reasons to Stay Hydrated

It Lowers the Risk of Heart Attacks

The heart is one of the most important organs, pumping blood to the rest of the body. So it's important to keep it healthy.

According to the NIH, coronary heart disease, when your arteries clog up with plaque, is the number one cause of death for both men and women in the United States. A worsening of coronary heart disease can lead to a heart attack. The best way to prevent it? Drink more water.

One study in the American Journal of Epidemiology showed that drinking more water is associated with a decrease in the risk of coronary heart disease. And drinking liquids other than water actually increased the chances of the disease.